Gibsons
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gibsons clear sky chart from 2005-11-05 to 2017-12-20.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.
Observation TypeMinimum conditions for hour to be usableOut of hours
Clear of CloudsTransparencySeeingSky Brightness
Planetary:50%(no limit)Average(no limit)Nighttime Hours
Deep Sky:70%Average(no limit)5.9Nighttime Hours
CCD Imaging:70%Below AveragePoor(no limit)Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

PlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
Night
41%
14871
9%
47969
8%
14843
43%
14843
14%
36208

By Month

MonthDays of MonthPlanetaryData
Pts
Deep Sky
Max 60%
Data
Pts
Both Planetary and Deep Sky
Max 60%
Data
Pts
Either Planetary or Deep SkyData
Pts
CCD ImagingData
Pts
January1st to 15thNight
26%
750
10%
2686
7%
746
30%
746
8%
2207
January16th to endNight
31%
785
8%
2762
7%
785
33%
785
9%
2244
February1st to 15thNight
31%
699
6%
2288
5%
699
34%
699
9%
1897
February16th to endNight
32%
632
11%
2053
9%
632
36%
632
13%
1584
March1st to 15thNight
24%
720
4%
2049
3%
720
25%
720
8%
1780
March16th to endNight
28%
768
6%
2085
4%
768
29%
768
9%
1793
April1st to 15thNight
40%
698
8%
1778
4%
698
41%
698
14%
1431
April16th to endNight
40%
516
9%
1596
8%
516
42%
516
13%
1224
May1st to 15thNight
54%
359
12%
1439
19%
359
57%
359
17%
954
May16th to endNight
55%
374
7%
1430
10%
374
57%
374
14%
996
June1st to 15thNight
54%
360
3%
1260
2%
360
54%
360
18%
872
June16th to endNight
55%
360
5%
1260
2%
360
55%
360
17%
875
July1st to 15thNight
75%
340
9%
1190
8%
340
75%
340
35%
640
July16th to endNight
79%
376
13%
1302
19%
354
81%
354
36%
657
August1st to 15thNight
80%
444
15%
1517
19%
442
80%
442
36%
784
August16th to endNight
71%
597
19%
1743
18%
597
72%
597
34%
1035
September1st to 15thNight
73%
720
22%
1800
13%
720
75%
720
43%
1078
September16th to endNight
47%
716
16%
1982
12%
716
49%
716
21%
1428
October1st to 15thNight
49%
720
11%
2160
10%
720
51%
720
22%
1504
October16th to endNight
34%
768
8%
2408
7%
768
37%
768
11%
1894
November1st to 15thNight
20%
760
5%
2660
4%
760
22%
760
6%
2262
November16th to endNight
23%
780
6%
2730
4%
780
27%
780
7%
2261
December1st to 15thNight
29%
806
7%
2841
5%
806
32%
806
9%
2322
December16th to endNight
18%
823
7%
2950
3%
823
23%
823
7%
2486

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

Occurrence of each ForecastData
Points
Cloud CoverDay
23%7%35%42445%6%32%
48905
Night
27%7%35%424345%30%
48120
Cloud CoverDay
24%6%25%5%2445%5%32%
48905
Night
28%8%25%423345%30%
48123
TransparencyDay
52%11%12%15%6%1
48559
Night
56%7%11%15%6%1
47970
SeeingDay
23%318%27%22%4
6480
Night
31%316%23%19%4
14878

By Month

Percentage Cloud Cover NW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
42%9%345%2443314%
1253
16th to endDay
36%8%26%6%23445%17%
1458
February1st to 15thDay
36%8%46%4345%5%417%
1576
16th to endDay
24%8%35%5%35%5%5%8%24%
1421
March1st to 15thDay
38%9%47%6%23445%13%
1909
16th to endDay
31%10%37%6%2423422%
2139
April1st to 15thDay
23%9%38%5%35%46%6%22%
2170
16th to endDay
24%8%45%42445%6%28%
2364
May1st to 15thDay
17%6%26%5%3435%7%36%
2511
16th to endDay
18%6%35%5%35%5%6%8%30%
2680
June1st to 15thDay
18%6%36%5%35%45%8%33%
2700
16th to endDay
19%5%25%5%3446%7%35%
2700
July1st to 15thDay
9%32342345%6%54%
2700
16th to endDay
9%31231335%6%59%
2777
August1st to 15thDay
8%414323346%57%
2433
16th to endDay
8%42442346%7%49%
2459
September1st to 15thDay
9%424323346%52%
2160
16th to endDay
24%5%2432435%8%34%
1976
October1st to 15thDay
28%5%34424446%30%
1800
16th to endDay
35%8%25%323346%22%
1813
November1st to 15thDay
45%8%25%322335%18%
1528
16th to endDay
40%9%35%32444418%
1560
December1st to 15thDay
30%12%45%5%3444420%
1446
16th to endDay
43%11%245%2332414%
1372
January1st to 15thNight
39%8%35%42334420%
2686
16th to endNight
33%9%35%42345%6%20%
2762
February1st to 15thNight
35%9%25%434446%19%
2276
16th to endNight
26%9%35%5%24446%29%
2053
March1st to 15thNight
38%9%46%42434417%
2049
16th to endNight
31%9%46%5%25%445%19%
2081
April1st to 15thNight
24%8%35%5%45%5%5%6%25%
1778
16th to endNight
23%8%36%6%3435%6%28%
1596
May1st to 15thNight
16%5%26%5%35%45%7%37%
1439
16th to endNight
16%7%35%6%345%5%8%32%
1430
June1st to 15thNight
19%7%37%5%24325%37%
1260
16th to endNight
15%6%25%6%35%5%5%7%35%
1260
July1st to 15thNight
7%413324336%59%
1260
16th to endNight
7%212213346%61%
1391
August1st to 15thNight
5%31332345%6%61%
1525
16th to endNight
9%32442345%7%51%
1743
September1st to 15thNight
8%312324345%60%
1800
16th to endNight
23%6%245%22445%37%
1982
October1st to 15thNight
22%6%24423346%39%
2160
16th to endNight
35%6%24423336%26%
2408
November1st to 15thNight
41%8%35%42333418%
2660
16th to endNight
37%9%25%5%3323420%
2730
December1st to 15thNight
32%11%36%5%24435%20%
2841
16th to endNight
41%11%35%41232418%
2950

Percentage Cloud Cover SW (2006-)
Color Meanings:
Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
41%9%36%42333316%
1253
16th to endDay
37%8%26%5%24345%18%
1458
February1st to 15thDay
35%9%36%5%3445%418%
1576
16th to endDay
24%9%35%5%26%36%6%24%
1421
March1st to 15thDay
39%9%36%6%3433415%
1909
16th to endDay
32%10%38%6%3433420%
2139
April1st to 15thDay
25%8%38%6%36%46%5%21%
2170
16th to endDay
25%7%45%5%35%5%5%5%27%
2364
May1st to 15thDay
17%6%25%6%3446%6%35%
2511
16th to endDay
18%7%36%5%35%5%6%8%29%
2680
June1st to 15thDay
18%7%36%5%25%46%7%32%
2700
16th to endDay
18%6%25%5%35%45%6%34%
2700
July1st to 15thDay
9%42432335%6%53%
2700
16th to endDay
10%312323346%58%
2777
August1st to 15thDay
8%323413346%56%
2433
16th to endDay
10%42442436%7%48%
2459
September1st to 15thDay
10%315%42445%6%51%
2160
16th to endDay
26%42442445%6%34%
1976
October1st to 15thDay
29%6%24423345%32%
1800
16th to endDay
36%7%34413346%22%
1813
November1st to 15thDay
45%9%2432333318%
1528
16th to endDay
41%7%35%42443318%
1560
December1st to 15thDay
30%12%36%5%2433423%
1446
16th to endDay
46%8%35%42332416%
1372
January1st to 15thNight
39%9%35%42233421%
2685
16th to endNight
34%8%35%5%23346%20%
2762
February1st to 15thNight
36%9%34424445%19%
2276
16th to endNight
26%9%36%5%23345%28%
2053
March1st to 15thNight
40%9%36%5%2343316%
2049
16th to endNight
34%9%36%6%3443418%
2085
April1st to 15thNight
25%9%35%5%445%5%6%24%
1778
16th to endNight
23%9%35%5%35%45%6%26%
1596
May1st to 15thNight
17%425%6%35%46%7%37%
1439
16th to endNight
15%7%36%5%35%45%8%33%
1430
June1st to 15thNight
18%7%35%433445%37%
1260
16th to endNight
14%7%36%6%45%5%45%36%
1260
July1st to 15thNight
8%323323347%58%
1260
16th to endNight
6%313313446%61%
1391
August1st to 15thNight
6%31332345%6%60%
1525
16th to endNight
9%41432345%7%52%
1743
September1st to 15thNight
7%31332335%460%
1800
16th to endNight
23%7%15%423336%37%
1982
October1st to 15thNight
23%6%24323346%39%
2160
16th to endNight
37%6%24323335%25%
2408
November1st to 15thNight
43%9%26%5%2332416%
2660
16th to endNight
39%8%15%6%2333321%
2730
December1st to 15thNight
33%11%35%5%2443422%
2841
16th to endNight
42%11%25%32232318%
2950

Transparency (when cloud cover <= 30%)
Color Meanings:
Too cloudy to forecast Poor Below Average Average Above average Transparent
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
71%6%7%8%5%1
1253
16th to endDay
69%7%9%9%21
1458
February1st to 15thDay
68%9%7%7%32
1576
16th to endDay
57%12%12%11%4
1421
March1st to 15thDay
73%9%8%6%2
1909
16th to endDay
68%8%9%11%1
2139
April1st to 15thDay
61%13%10%11%2
2170
16th to endDay
58%11%11%12%5%
2364
May1st to 15thDay
48%13%12%18%6%
2511
16th to endDay
52%15%12%16%2
2684
June1st to 15thDay
49%13%16%14%41
2700
16th to endDay
48%14%15%15%5%
2700
July1st to 15thDay
31%11%17%24%12%2
2541
16th to endDay
25%12%19%29%10%1
2603
August1st to 15thDay
28%12%17%29%10%1
2416
16th to endDay
32%11%19%27%6%1
2459
September1st to 15thDay
32%11%14%22%16%2
2160
16th to endDay
51%11%13%15%7%1
1976
October1st to 15thDay
53%10%13%14%7%
1800
16th to endDay
63%10%11%9%4
1813
November1st to 15thDay
71%8%8%6%31
1528
16th to endDay
69%8%5%10%5%
1560
December1st to 15thDay
66%7%7%9%6%2
1446
16th to endDay
74%5%7%7%31
1372
January1st to 15thNight
68%6%6%12%5%1
2686
16th to endNight
66%7%8%12%31
2762
February1st to 15thNight
67%7%9%9%32
2288
16th to endNight
58%8%10%15%5%1
2053
March1st to 15thNight
71%8%8%9%2
2049
16th to endNight
69%8%8%12%2
2085
April1st to 15thNight
58%10%10%16%4
1778
16th to endNight
57%8%12%16%5%
1596
May1st to 15thNight
45%9%15%20%8%1
1440
16th to endNight
49%9%16%19%4
1430
June1st to 15thNight
50%6%19%16%5%1
1260
16th to endNight
48%9%15%20%5%1
1260
July1st to 15thNight
28%6%18%28%14%3
1190
16th to endNight
21%10%19%30%15%2
1302
August1st to 15thNight
23%9%21%27%14%3
1517
16th to endNight
30%8%19%28%10%2
1743
September1st to 15thNight
25%8%15%26%19%4
1800
16th to endNight
48%7%11%21%7%2
1982
October1st to 15thNight
47%6%15%18%11%
2160
16th to endNight
62%7%12%12%5%
2408
November1st to 15thNight
72%6%8%7%31
2660
16th to endNight
68%7%7%9%6%
2730
December1st to 15thNight
67%6%8%9%5%1
2841
16th to endNight
71%6%6%9%5%
2950

Seeing (when cloud cover <= 80%)
Color Meanings:
Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
MonthDays in MonthOccurrence of each ForecastData
Points
January1st to 15thDay
21%6%15%28%16%11%
60
16th to endDay
52%5%20%12%7%1
88
February1st to 15thDay
41%5%19%18%14%
236
16th to endDay
31%5%25%19%15%2
211
March1st to 15thDay
46%7%24%15%41
270
16th to endDay
37%5%28%18%8%1
288
April1st to 15thDay
33%323%20%17%2
269
16th to endDay
24%326%29%12%2
270
May1st to 15thDay
20%324%32%17%1
288
16th to endDay
16%317%26%30%5%
395
June1st to 15thDay
16%219%34%22%4
495
16th to endDay
16%19%34%25%3
495
July1st to 15thDay
9%112%37%34%5%
475
16th to endDay
6%13%36%37%6%
446
August1st to 15thDay
9%10%29%40%10%
315
16th to endDay
10%114%38%30%4
332
September1st to 15thDay
14%220%31%24%6%
315
16th to endDay
24%219%27%17%8%
315
October1st to 15thDay
34%220%24%15%2
315
16th to endDay
44%6%11%20%14%3
260
November1st to 15thDay
52%7%22%8%8%
90
16th to endDay
54%411%11%10%8%
90
December1st to 15thDay
42%5%8%23%15%4
90
16th to endDay
43%8%20%18%8%1
72
January1st to 15thNight
42%320%19%12%1
750
16th to endNight
38%418%24%14%
785
February1st to 15thNight
40%416%25%13%
704
16th to endNight
32%5%23%23%11%3
632
March1st to 15thNight
43%5%19%17%12%1
720
16th to endNight
37%6%18%21%13%2
768
April1st to 15thNight
30%415%29%16%4
698
16th to endNight
27%319%28%18%2
516
May1st to 15thNight
18%215%29%26%7%
360
16th to endNight
18%313%28%31%5%
375
June1st to 15thNight
21%112%27%28%8%
360
16th to endNight
17%111%32%31%5%
360
July1st to 15thNight
10%7%27%42%12%
340
16th to endNight
7%6%19%51%15%
376
August1st to 15thNight
8%320%46%19%
444
16th to endNight
11%19%22%45%10%
597
September1st to 15thNight
8%111%26%37%14%
720
16th to endNight
27%313%23%23%8%
716
October1st to 15thNight
27%117%29%20%3
720
16th to endNight
39%415%24%13%2
768
November1st to 15thNight
46%6%21%20%5%
760
16th to endNight
43%421%18%10%2
780
December1st to 15thNight
38%420%26%9%
806
16th to endNight
47%425%17%5%
823
Page generated at 2017-12-21 04:04:54. Version ac04

Copyright 2017 A. Danko


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